Relationship of dough extensibility to dough strength in a spring wheat cross

A negative relationship between dough strength and dough extensibility would pose a problem for breeding hard wheats, as both dough strength and dough extensibility are desirable. We derived 77 recombinant inbred lines (RIL) from a cross between hard red spring wheat cultivars McNeal and Thatcher. McNeal produces flour with stronger dough and lower extensibility than does Thatcher. RIL were evaluated for strength-related properties using mixograph analysis and extensibility parameters using the Kieffer attachment to the TA.XT2 texture analyzer. Additionally, the RIL were test baked. Measurements using the mixograph and the Kieffer attachment were highly heritable. Maximum dough extensibility (Ext(max)) was negatively correlated with resistance to extension (R-max) (r = -0.74) and with mixograph tolerance (r = -0.45). Loaf volume was correlated with both R-max (r = 0.42) and area under the extensigraph curve (r = 0.44) based on partial correlation analysis adjusted for protein differences. Ext(max) was negatively correlated with loaf volume (r = -0.26). The McNeal allele for polymorphism at the Gli1-B1 locus on chromosome 1BS caused high dough-mixing tolerance and low dough extensibility. Our results suggest that traditional selection criteria in hard red spring wheat, including tolerance to dough mixing and high loaf volume, may result in reduced dough extensibility.